导弹密封圈用硅橡胶热降解动力学研究

Study on Thermal Degradation Kinetics of Silicone Rubber in Sealing Ring for Missile

采用热失重法(TG)及微分热失重法(DTG)考察了随弹自然贮存10年的6101甲基乙烯基硅橡胶混炼胶O型密封圈材料的热稳定性,通过微分与积分的动力学方法算得6101混炼胶的热降解活化能,并采用Crane法对其反应级数进行了分析计算。结果表明,N_2气氛下,6101混炼胶热降解过程分两步进行。升温速度为5℃/min时,6101混炼胶的起始降解温度为445.7℃,最大降解速率时的温度为619.8℃。其热降解活化能约为237.9 kJ/mol,反应级数为1.05级,反应主要受随机成核与生长机理控制。

The thermal stability of methyl vinyl 6101 silicone rubber compounds after 10 years on-missile storage was investigated by thermogravimetry（TG） and derivative thermogravimetry（DTG）. The thermal deg- radation activation energy of 6101 rubber compounds was evaluated by the dynamics of differential and inte- gral, and its reaction order （n） was evaluated by Crane method. Results show that the thermal degradation process of 6101 rubber compounds is carried on by two steps in N2 atmosphere. As the heating rate is 5℃/min, the initial degradation temperature of 6101 rubber is 445.7℃, and the temperature at the maximum degradation rate is 619.8℃. The thermal and reaction order of Grade 1.05 mation and growth mechanism. degradation activation energy of silicone rubber compounds is 237.9 kJ/mol, The thermal degradation is controlled by the process of random nuclear for-